One-pot synthesis of SiO2‒CeO2 nanoparticle composites with enhanced heat tolerance

We propose a novel method for the fabrication of CeO2 nanoparticles (NPs) with enhanced heat tolerance. SiO2 was mixed with CeO2 at the nano-level to yield SiO2‒CeO2 NP composites by a solvothermal reaction of precursor solutions consisting of Si(OEt)4, Ce(NO3)3·6H2O, and N,N,N′,N′-tetramethylethylenediamine in methanol. SiO2 content in the SiO2‒CeO2 NP composites was freely controllable by adjusting the Si(OEt)4 mol fraction in range of 0–0.5 in the precursor solutions. With an increase of SiO2 content in the SiO2‒CeO2 NP composites, the primary particle sizes of the CeO2 NPs decreased, and the specific surface areas of the SiO2‒CeO2 NP composites increased remarkably. For SiO2‒CeO2 NP composites obtained from a precursor solution consisting of 1:1 Si(OEt)4 and Ce(NO3)3·6H2O, the specific surface area was over 300 m2/g. Excellent heat tolerance was achieved through the retention of small size of CeO2 crystallites, as well as the large specific surface areas of the SiO2‒CeO2 NP assemblies, even after calcination at 850 °C for 3 h or at 700 °C for 72 h in air.